Increased levels of γ‐glutamylamines in Huntington disease CSF

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Journal of Neurochemistry (Impact Factor: 4.28). 08/2008; 106(1):37-44. DOI: 10.1111/j.1471-4159.2008.05350.x
Source: PubMed


Transglutaminases (TGases) catalyze several reactions with protein substrates, including formation of gamma-glutamyl-epsilon-lysine cross-links and gamma-glutamylpolyamine residues. The resulting gamma-glutamylamines are excised intact during proteolysis. TGase activity is altered in several diseases, highlighting the importance of in situ enzymatic determinations. Previous work showed that TGase activity (as measured by an in vitro assay) and free gamma-glutamyl-epsilon-lysine levels are elevated in Huntington disease (HD) and that gamma-glutamyl-epsilon-lysine is increased in HD CSF. Although free gamma-glutamyl-epsilon-lysine was used in these studies as an index of in situ TGase activity, gamma-glutamylpolyamines may also be diagnostic. We have devised methods for the simultaneous determination of four gamma-glutamylamines in CSF: gamma-glutamyl-epsilon-lysine, gamma-glutamylspermidine, gamma-glutamylputrescine, and bis-gamma-glutamylputrescine and showed that all are present in normal human CSF at concentrations of approximately 150, 670, 40, and 240 nM, respectively. The high gamma-glutamylspermidine/gamma-glutamylputrescine and gamma-glutamylspermidine/bis-gamma-glutamylputrescine ratios presumably reflect in part the large spermidine to putrescine mole ratio in human brain. We also showed that all four gamma-glutamylamines are elevated in HD CSF. Our findings support the hypotheses that (i) gamma-glutamylpolyamines are reflective of TGase activity in human brain, (ii) polyamination is an important post-translational modification of brain proteins, and (iii) TGase-catalyzed modification of proteins is increased in HD brain.

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    • "Alternatively, TG2 is involved in autophagosome maturation, and SPD-induced autophagy is able to promote longevity of yeast (D'Eletto et al. 2009; Morselli et al. 2009). In addition, TG2 may contribute to neurodegeneration through cross-linking or polyamination of the brain proteins such as amyloid-β, tau, α-synuclein, and huntingtin (Jeitner et al. 2008, 2009, 2013). In particular , γ-glutamyl polyamines in human CSF are elevated in CSF from Huntington disease patients. "
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    ABSTRACT: The polyamines spermidine and spermine, and their precursor putrescine, have been shown to play an important role in cell migration, proliferation, and differentiation. Because of their polycationic property, polyamines are traditionally thought to be involved in DNA replication, gene expression, and protein translation. However, polyamines can also be covalently conjugated to proteins by transglutaminase 2 (TG2). This modification leads to an increase in positive charge in the polyamine-incorporated region which significantly alters the structure of proteins. It is anticipated that protein polyamine conjugation may affect the protein–protein interaction, protein localization, and protein function of the TG2 substrates. In order to investigate the roles of polyamine modification, we synthesized a spermine-conjugated antigen and generated an antiserum against spermine. In vitro TG2-catalyzed spermine incorporation assays were carried out to show that actin, tubulins, heat shock protein 70 and five types of histone proteins were modified with spermine, and modification sites were also identified by liquid chromatography and linear ion trap-orbitrap hybrid mass spectrometry. Subsequent mass spectrometry-based shotgun proteomic analysis also identified 254 polyaminated sites in 233 proteins from the HeLa cell lysate catalyzed by human TG2 with spermine, thus allowing, for the first time, a global appraisal of site-specific protein polyamination. Global analysis of mouse tissues showed that this modification really exists in vivo. Importantly, we have demonstrated that there is a new histone modification, polyamination, in cells. However, the functional significance of histone polyamination demands further investigations.
    Amino Acids 12/2014; 47(3). DOI:10.1007/s00726-014-1879-8 · 3.29 Impact Factor
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    • "Similarly, the presence of TG crosslinked a-synuclein in substantia nigra dopaminergic neurons of Parkinson's disease patients has been demonstrated (Andringa et al. 2004). The fact that increased levels of the c-glutamyl-e-lysine crosslink as well as bis-c-glutamylpolyamine are found in the affected tissue and in the cerebrospinal fluid (Zainelli et al. 2003; Nemes et al. 2004; Jeitner et al. 2008) indicates that TG2 and possibly other TG isozymes extensively modify proteins and possibly also diseasespecific protein aggregates. Mouse models have substantiated a direct role of TG2 in the pathogenesis of Huntington's and other neurodegenerative diseases albeit the mechanisms involved being somewhat unexpected. "
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    ABSTRACT: Transglutaminases (TG) form a family of enzymes that catalyse various post-translational modifications of glutamine residues in proteins and peptides including intra- and intermolecular isopeptide bond formation, esterification and deamidation. We have characterized a novel member of the mammalian TG family, TG6, which is expressed in a human carcinoma cell line with neuronal characteristics and in mouse brain. Besides full-length protein, alternative splicing results in a short variant lacking the second β-barrel domain in man and a variant with truncated β-sandwich domain in mouse. Biochemical data show that TG6 is allosterically regulated by Ca2+ and guanine nucleotides. Molecular modelling indicates that TG6 could have Ca2+ and GDP-binding sites related to those of TG3 and TG2, respectively. Localization of mRNA and protein in the mouse identified abundant expression of TG6 in the central nervous system. Analysis of its temporal and spatial pattern of induction in mouse development indicates an association with neurogenesis. Neuronal expression of TG6 was confirmed by double-labelling of mouse forebrain cells with cell type-specific markers. Induction of differentiation in mouse Neuro 2a cells with NGF or dibutyryl cAMP is associated with an upregulation of TG6 expression. Familial ataxia has recently been linked to mutations in the TGM6 gene. Autoantibodies to TG6 were identified in immune-mediated ataxia in patients with gluten sensitivity. These findings suggest a critical role for TG6 in cortical and cerebellar neurons. Electronic supplementary material The online version of this article (doi:10.1007/s00726-011-1091-z) contains supplementary material, which is available to authorized users.
    Amino Acids 10/2011; 44(1). DOI:10.1007/s00726-011-1091-z · 3.29 Impact Factor
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    • "In addition to these experimental findings, it has been shown that TGs and transglutaminase-catalyzed cross-links colocalize with pathological lesions in Alzheimer's disease brain [34–36]. Interestingly, a recent work showed the presence of bis γ-glutamyl putrescine in human CSF, which was increased in Huntington's disease (HD) CSF [37]. These are important experimental data which demonstrate that protein/peptides cross-links and protein/peptides cross-linking by polyamines do indeed occur in brain, and that these transglutaminase-catalyzed reaction products are increased in AD and HD brains. "
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    ABSTRACT: Transglutaminases are ubiquitous enzymes which catalyze posttranslational modifications of proteins. Recently, transglutaminase-catalyzed post-translational modification of proteins has been shown to be involved in the molecular mechanisms responsible for human diseases. Transglutaminase activity has been hypothesized to be involved also in the pathogenetic mechanisms responsible for several human neurodegenerative diseases. Alzheimer's disease and other neurodegenerative diseases, such as Parkinson's disease, supranuclear palsy, Huntington's disease, and other polyglutamine diseases, are characterized in part by aberrant cerebral transglutaminase activity and by increased cross-linked proteins in affected brains. This paper focuses on the possible molecular mechanisms by which transglutaminase activity could be involved in the pathogenesis of Alzheimer's disease and other neurodegenerative diseases, and on the possible therapeutic effects of selective transglutaminase inhibitors for the cure of patients with diseases characterized by aberrant transglutaminase activity.
    International Journal of Alzheimer's Disease 02/2011; 2011(8):865432. DOI:10.4061/2011/865432
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